It does say something about the culture. That said, DD2 interviewed at 16 schools last year, and she got 16 handwritten notes. So it’s a nice comment on culture, but perhaps not a differentiating one. (however, I will say some were far more detailed than others. I was amazed by how long some of the notes were!)
Oh and to prepare you in advance: you just made the Christmas card list for those schools too.